1 using System;
2
3 abstract class State
4 {
5 protected string strStatename;
6
7 abstract public void Pour();
8 // do something state-specific here
9 }
10
11 class OpenedState : State
12 {
13 public OpenedState ()
14 {
15 strStatename = "Opened";
16 }
17 override public void Pour()
18 {
19 Console.WriteLine("...pouring...");
20 Console.WriteLine("...pouring...");
21 Console.WriteLine("...pouring...");
22 }
23 }
24
25 class ClosedState : State
26 {
27 public ClosedState()
28 {
29 strStatename = "Closed";
30 }
31 override public void Pour()
32 {
33 Console.WriteLine("ERROR - bottle is closed - cannot pour");
34 }
35 }
36
37 class ContextColaBottle
38 {
39 public enum BottleStateSetting {
40 Closed,
41 Opened
42 };
43
44 // If teh state classes had large amounts of instance data,
45 // we could dynamically create them as needed - if this demo
46 // they are tiny, so we just create them as data members
47 OpenedState openedState = new OpenedState();
48 ClosedState closedState = new ClosedState();
49
50 public ContextColaBottle ()
51 {
52 // Initialize to closed
53 CurrentState = closedState;
54 }
55
56 private State CurrentState;
57
58 public void SetState(BottleStateSetting newState)
59 {
60 if (newState == BottleStateSetting.Closed)
61 {
62 CurrentState = closedState;
63 }
64 else
65 {
66 CurrentState = openedState;
67 }
68 }
69
70 public void Pour()
71 {
72 CurrentState.Pour();
73 }
74 }
75
76 /// <summary>
77 /// Summary description for Client.
78 /// </summary>
79 public class Client
80 {
81 public static int Main(string[] args)
82 {
83 ContextColaBottle contextColaBottle = new ContextColaBottle();
84
85 Console.WriteLine("initial state is closed");
86
87 Console.WriteLine("Now trying to pour");
88 contextColaBottle.Pour();
89
90 Console.WriteLine("Open bottle");
91 contextColaBottle.SetState(ContextColaBottle.BottleStateSetting.Opened);
92
93 Console.WriteLine("Try to pour again");
94 contextColaBottle.Pour();
95
96 return 0;
97 }
98 }
